<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  <h1>second</h1>

  <input type="button" value="后退" id="btn1">

  <script>
    var btn1 = document.getElementById('btn1');
    btn1.onclick = function () {
      // history.back();
      history.go(-1);
    }
  </script>
</body>
</html>
